I'll give the facts. I'll give all my details. I'm Barry Gordon. I'm thirteen."" So begins young Barry's account of what happened one summer-vacation night in Cornwall: a little tale, somewhere between fantasy and science fiction, that's less-than-magical yet more than nicely told. Swimming out too far one day, Barry spots the entrance to a cliff cave, nearly drowns, and is warned against such adventuring. But he's drawn back to the cliff a few nights later, boldly jumps onto a platform of rock, then is beckoned aboard a canoe by a naked, white-haired boy named Dido. And somehow the canoe is a submarine, with steps going down to a door: Barry has entered ""inner space. . . a world under the sea. The real world. Egon."" Giants reside there. People live to be 800 (youngster Dido is 99). There's no pain. There are dangerous games like power-tobogganing and sky-chasing. And under Plum Lake ""you swing in your hammock, and watch the ragusa grow, and you can't stop laughing. You tell jokes."" So, despite a scare or two--he nearly dies while sky-chasing and gets a dreadful glimpse way down below of ""the world creating itself""--Barry is exhilarated (""I've seen the future, and it's wonderful""), learning that life is ""fun"" and ""magic."" But he must go back home, of course. And though his Egon memories were supposedly erased, he remembers--with concrete evidence (his sky-chasing fracture, perfectly reset and healed) to prove that it wasn't all a dream. So Barry's left discontented: wanting to get on with real life, yet wanting to go back to Egon again. . . . Is this a parable, like most such voyages, of the conflict between the imaginative/pleasure impulse and earthbound reality? Perhaps. But Davidson's rather linear version lacks the truly dreamlike, inevitable, shapely quality of the best variations; his wonderland often seems too much like Disneyland (rides, food, rainbow colors); and Barry's adjectival dependence on ""weird"" and ""fantastic,"" though perhaps accurately adolescent, is a drag. Still, most of the visual description is leanly lovely--walls turning transparent, geology made poetry. And above all, Davidson's ability to sustain a strange, floating tone through Barry's spare, almost primitive narration is impressive: another inkling of great talent from a writer (Murder Games, The Sun Chemist, The Menorah Men) whose oddly conceived books are usually--like this one--less than fully satisfying.